With charter schools educating as many as half the students in some American cities, they have been championed as a lifeline for poor black children stuck in failing traditional public schools.

But now the nation’s oldest and newest black civil rights organizations are calling for a moratorium on charter schools.

Their demands, and the outcry that has ensued, expose a divide among blacks that goes well beyond the now-familiar complaints about charters’ diverting money and attention from traditional public schools.

In separate conventions over the past month, the N.A.A.C.P. and the Movement for Black Lives, a group of 50 organizations assembled by Black Lives Matter, passed resolutions declaring that charter schools have exacerbated segregation, especially in the way they select and discipline students.

They portray charters as the pet project of foundations financed by white billionaires, and argue that the closing of traditional schools as students migrate to charters has disproportionately disrupted black communities.

There’s also the many problems with how charter schools operate:

Although charters are supposed to admit students by lottery, some effectively skim the best students from the pool, with enrollment procedures that discourage all but the most motivated parents to apply. Some charters have been known to nudge out their most troubled students.

That, the groups supporting a moratorium say, concentrates the poorest students in public schools that are struggling for resources.

Charter schools “are allowed to get away with a lot more,” said Hiram Rivera, an author of the Black Lives platform and the executive director of the Philadelphia Student Union.

Charters are slightly more likely to suspend students than traditional public schools, according to an analysis of federal data this year. And black students in charter schools are four times as likely to be suspended as their white peers, according to the data analysis, putting them in what Mr. Brooks calls the “preschool to prison pipeline.”

Another platform author, Jonathan Stith, the national coordinator for the Alliance for Educational Justice, chose a charter school in Washington for one of his children because it promised an Afrocentric curriculum. But he began to see the school driving out students. It was difficult, he said, for parents to push back against the private boards that run the schools.

“Where you see the charters providing an avenue of escape for some, it hasn’t been for the majority,” he said.

Mr. Stith came to think the money would be better spent on fixing the traditional public school system.

Once again, the problem of education is the problems of poverty and inequality. If you want to improve public education, you don’t give over public monies and responsibility to private entities. You work to fix poverty. But where’s the money for that? Plus if you fixed poverty there might be room for teachers’ unions and we couldn’t have that now, could we. After all, who is more concerned about a child’s education, a Silicon Valley investor or a teacher trying to reach out to a children and pay her mortgage at the same time?